Process for producing N-halogenated hydantoins

ABSTRACT

This invention provides a process for the N-halogenation of at least one 5-hydrocarbyl hydantoin and/or at least one 5,5-dihydrocarbyl hydantoin. The process comprises concurrently feeding into a reaction zone (i) water, inorganic base, and 5,5-dimethylhydantoin, these being fed separately and/or in any combination(s), (ii) a separate feed of a brominating agent, and (iii) a separate feed of a chlorinating agent, in proportions such that during all or substantially all of the time the concurrent feeding is occurring halogenation of the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin occurs and resultant halogenated product precipitates in the liquid phase of an aqueous reaction mixture, and in which the pH of the liquid phase is continuously or substantially continuously maintained in the range of about 2.0 to about 8.0 during all or substantially all of the time the concurrent feeding is occurring. Also provided by this invention is a composition of matter which is a halogenated 5-hydrocarbyl hydantoin or a halogenated 5,5-dihydrocarbyl hydantoin, which is a mixture of the 1,3-dibromo-, 1,3-dichloro-, and/or N,N′-bromochloro-species of the halogenated hydantoin.

REFERENCE TO RELATED APPLICATIONS

This is a Continuation-in-Part of commonly-owned prior application Ser.No. 10/919,097, filed Aug. 16, 2004, now abandoned, which is in turn aContinuation-in-Part of commonly-owned prior application Ser. No.09/484,844, filed Jan. 18, 2000, now U.S. Pat. No. 6,809,205, alldisclosure of which is incorporated herein by reference.

REFERENCE TO OTHER APPLICATIONS

Commonly-owned application Ser. No. 09/484,687, filed Jan. 18, 2000, nowU.S. Pat. No. 6,508,954, by me and some of my colleagues, describes andclaims 1,3-dibromo-5,5-dimethylhydantoin particulate solids producibleby the processes of this application, such solids having unprecedentedenhanced properties, and compacted articles made from such particulatesolids without use of a binder. Commonly-owned application Ser. No.09/487,816, filed Jan. 18, 2000, now U.S. Pat. No. 6,680,070, by some ofmy colleagues, relates in part to converting1,3-dihalo-5,5-dimethylhydantoins into compacted articles using novelbinders. Commonly-owned copending application Ser. No. 09/484,938, filedJan. 18, 2000, now U.S. Pat. No. 6,565,868, by some of my colleagues,describes and claims methods for effecting efficacious microbiologicalcontrol utilizing 1,3-dibromo-5,5-dimethylhydantoin in novel compactedor non-compacted forms. Commonly-owned application Ser. No. 09/484,891,filed Jan. 18, 2000, now U.S. Pat. No. 6,495,698, by one of mycolleagues relates to the compacting of1,3-dihalo-5,5-dimethylhydantoins other than1,3-dibromo-5,5-dimethylhydantoin without use of binders, and to thenovel compacted forms so produced. Commonly-owned application Ser. No.09/483,896, filed Jan. 18, 2000, now U.S. Pat. No. 6,448,410, by some ofmy colleagues relates to the granulation of small average particle size1,3-dibromo-5,5-dimethylhydantoin and also to the compaction of suchgranulated products to form larger-sized articles.

TECHNICAL FIELD

This invention relates to novel, highly efficient processes for thepreparation of 1,3-dihalo-5-alkylhydantoins and1,3-dihalo-5,5-dialkylhydantoins. As used herein, such terms as halogen,halogenated, and halo refer to bromine and/or chlorine.

BACKGROUND

1,3-Dihalo-5,5-dialkylhydantoins, especially1,3-dibromo-5,5-dimethylhydantoin, 1,3-dichloro-5,5-dimethylhydantoin,1-bromo-3-chloro-5,5-dimethylhydantoin, and1-chloro-3-bromo-5,5-dimethylhydantoin, or mixtures of two or more ofthem, are biocidal agents for use in water treatment. These compoundsare, in general, sparingly soluble in water.

Over the years considerable effort has been devoted to the search forimproved methods for producing N-halogenated hydantoins. In U.S. Pat.No. 2,971,960 N-brominated compounds such as N-brominated5,5-di-lower-alkyl hydantoins are formed by treating the alkylhydantoinwith bromine in an acidic aqueous solution containing hypochlorite,preferably at a pH between 1 and 4. However, the method of choice hasbeen halogenation of the alkylhydantoin in a basic aqueous medium.Almost invariably the halogen has been introduced into, or formed insitu in, the aqueous medium containing the alkylhydantoin. See in thisconnection U.S. Pat. Nos. 2,398,598; 2,779,764; 2,868,787; 2,920,997;2,971,959; 3,121,715; 3,147,259; 4,532,330; 4,560,766; 4,654,424;4,677,130; 4,745,189; WO 97/43264, published 20 Nov. 1997; Orazi andMeseri, Anales Assoc. Quim. Argentina, 1949, 37, 192-196; Orazi andMeseri, Anales Assoc. Quim. Argentina, 1950, 38, 5-11; Corral and Orazi,J. Org. Chem., 1963, 23, 1100-1104; Jolles, Bromine and its Compounds,Ernest Benn, London, 1966, p. 365; and Markish and Arrad, Ind. Eng.Chem. Res., 1995, 34, 2125-2127.

Shortcomings of prior processes for the N-halogenation of hydantoinsinclude the requirement for careful temperature control (particularly inorder to avoid sudden exotherms), long reaction times, foaming due toevolution of gases from decomposition of reactants and/or reactionproducts, and products of inconsistent quality.

It would be of considerable advantage if a new way could be found ofproducing N-halogenated hydantoins while avoiding or at least minimizingthe extent of the shortcomings referred to above.

Another advantage would be the provision of process technology whichenables production in a single halogenation step or operation of“tailor-made” mixtures of 1,3-dihalo-5,5-dialkylhydantoins (preferably1,3-dihalo-5,5-dimethylhydantoins) even if such mixtures are not alwaysof larger average particle size. By “tailor-made” mixtures is meant thatthrough control or regulation of the halogenation process, it ispossible to produce a reaction product containing a mixture of1,3-dibromo-5,5-dialkylhydantoin together withN,N′-bromochloro-5,5-dialkylhydantoin(s) and optionally1,3-dichloro-5,5-dialkylhydantoin in which proportions of thesehalogenated products in the mixture can be controlled so as to be withinpredetermined experimental limits. Some of these mixtures are new, andare useful as cost-effective biocides especially for water treatmentapplications.

This invention is deemed to fulfill these objectives in a most effectiveand efficient manner.

SUMMARY OF INVENTION

This invention provides processes for producing mixtures of halogenatedhydantoins in a single halogenation step or operation. As used herein,the term “mixtures of halogenated hydantoins” refers to mixtures of1,3-dihalohydantoins, more particularly, 1,3-dihalo-5-hydrocarbylhydantoins and 1,3-dihalo-5,5-dihydrocarbyl hydantoins. At least some ofthese mixtures are new compositions of matter, which are useful ascost-effective biocides especially for water treatment applications. Anadvantage of this invention is that the parameters of the processes ofthe invention can be adjusted so that the mixtures produced are enrichedin the 1,3-dibromohydantoin or the N,N′-bromochlorohydantoin. Anotherfeature of this invention is that the average particle size of theproduct can be adjusted by adjusting the pH during the process. Thehalogenated hydantoins produced by the processes of this invention havegood color characteristics (i.e., products are often white oroff-white). In addition to the foregoing advantages, the processes ofthe invention are economical because the pH during the process, as wellas the distribution of halogenated hydantoins produced, can be adjustedby varying the rates of feeding of the reagents for the processes. Inother words, no additional component needs to be added to alter the pHor to enrich the product in a particular halogenated hydantoin.

In accordance with this invention processes are provided which arecharacterized by high efficiency, uniform product consistency, goodproduct color, and efficient utilization of reactants. In addition, thisinvention makes possible the conduct of exothermic N-halogenationreactions without use of costly refrigeration. Moreover, the processesof this invention can be run in a batch mode, in a semi-batch mode, orin a continuous mode, and in any such mode it is possible, whenproducing products devoid of chromophoric groups, to obtain high yieldsof very pale yellow to almost pure white products. And no haloorganicsolvent or co-solvent of any kind is required in the processes of thisinvention.

An embodiment of this invention is a process for the N-halogenation ofat least one 5-hydrocarbyl hydantoin and/or at least one5,5-dihydrocarbyl hydantoin. The process comprises concurrently feedinginto a reaction zone (i) water, inorganic base, and5,5-dimethylhydantoin, these being fed separately and/or in anycombination(s), (ii) a separate feed of a brominating agent, and (iii) aseparate feed of a chlorinating agent, in proportions such that duringall or substantially all of the time the concurrent feeding is occurringhalogenation of the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbylhydantoin occurs and resultant halogenated product precipitates in theliquid phase of an aqueous reaction mixture, and in which the pH of theliquid phase is continuously or substantially continuously maintained inthe range of about 2.0 to about 8.0 during all or substantially all ofthe time the concurrent feeding is occurring.

Another embodiment of this invention is a process for the N-halogenationof at least one 5-hydrocarbyl hydantoin and/or at least one5,5-dihydrocarbyl hydantoin. The process comprises:

-   -   A-1) concurrently or substantially concurrently feeding into in        a reaction zone maintained at one or more temperatures in the        range of about 20 to about 80° C., separate feeds of (i) an        aqueous solution or slurry formed from an inorganic base and at        least one 5-hydrocarbyl hydantoin and/or at least one        5,5-dihydrocarbyl hydantoin, (ii) a brominating agent, and (iii)        a chlorinating agent; or    -   A-2) concurrently or substantially concurrently feeding into a        reaction zone maintained at one or more temperatures in the        range of about 20 to about 80° C., at least four separate feeds,        one of which is a brominating agent, another of which is a        chlorinating agent, and at least two other feeds, at least one        of which is selected from (a) and (b); and at least one of which        is selected from (c) and (d), wherein        -   (a) is an aqueous solution or slurry formed from an            inorganic base,        -   (b) is an aqueous solution or slurry formed from an            inorganic base and at least one 5-hydrocarbyl hydantoin            and/or at least one 5,5-dihydrocarbyl hydantoin,        -   (c) at least one 5-hydrocarbyl hydantoin and/or at least one            5,5-dihydrocarbyl hydantoin, and        -   (d) is an aqueous solution or slurry formed from at least            one 5-hydrocarbyl hydantoin and/or at least one            5,5-dihydrocarbyl hydantoin;    -    wherein the concurrent or substantially concurrent feeds in A-1        or in A-2 are in proportions such that 5-hydrocarbyl hydantoin        and/or 5,5-dihydrocarbyl hydantoin is halogenated on both        nitrogen atoms by bromine and/or chlorine atoms, and product is        formed which precipitates in the aqueous reaction mixture        continuously or substantially continuously during all or        substantially all of the time the concurrent feeding is        occurring; and    -   B) preadjusting and/or adjusting or controlling (1) the ratio        between the brominating agent and the chlorinating agent fed        and (2) the amount of inorganic base fed such that the pH of the        mixture in the reaction zone is continuously or substantially        continuously maintained at a selected pH in the range of about        2.0 to about 5.5 during the time the concurrent or substantially        concurrent feeding is occurring.

Still another embodiment of this invention is a composition of matterwhich comprises a halogenated 5-hydrocarbyl hydantoin or a halogenated5,5-dihydrocarbyl hydantoin, which is a mixture of the 1,3-dibromo-,1,3-dichloro-, and/or N,N′-bromochloro-species of the halogenatedhydantoin.

These and other embodiments and features of this invention will be stillfurther apparent from the ensuing description and appended claims.

FURTHER DETAILED DESCRIPTION OF THE INVENTION

As used throughout this document, the term “halogenating agent” is usedto refer collectively to a brominating agent and a chlorinating agent.

The reactants used in the practice of this invention are comprised ofthe 5-hydrocarbyl and the 5,5-dihydrocarbyl hydantoins, with the5,5-dihydrocarbyl hydantoins being preferred. Particularly preferredhydantoins are the 5-alkyl and 5,5-dialkyl hydantoins, especially thosein which each alkyl group contains up to about 6 carbon atoms. Stillmore preferred are 5,5-dialkyl hydantoins in which each alkyl groupcontains, independently, up to 3 carbon atoms. Especially preferred is5,5-dimethylhydantoin.

A wide variety of inorganic bases are suitable for use in the process ofthis invention. Typically these are water-soluble basic salts or oxidesof an alkali metal or an alkaline earth metal. Preferred bases includesodium oxide, sodium hydroxide, sodium carbonate, sodium bicarbonate,potassium oxide, potassium hydroxide, potassium carbonate, potassiumbicarbonate, calcium oxide, calcium hydroxide, or a mixture of any twoor more of them.

In order to achieve the best results, the amount of base used is thestoichiometric quantity, or is substantially the stoichiometricquantity, theoretically required to deprotonate both nitrogen atoms ofthe 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin, i.e.,both the halogenatable amido group and the halogenatable imido group aredeprotonated.

When conducting the process embodiments of this invention, especiallywhen using a 5,5-dialkylhydantoin, more particularly5,5-dimethylhydantoin, the proportions of water, inorganic base, and5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin being fedshould be such that when using an inorganic base having a monovalentcation, there can be from about 0.5 to about 2.5 moles of 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin and from about 1.0 to about5.0 moles of the base, per liter of water being fed, and preferably fromabout 1.0 to about 1.5 moles of 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin and from about 2.0 to about 3.0 moles of thebase, per liter of water being fed. When using an inorganic base havinga divalent cation, there can be from about 0.5 to about 2.5 moles of5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin and fromabout 0.5 to about 2.5 moles of the base, per liter of water being fed,and preferably about 1.0 to about 1.5 moles of 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin and from about 1.0 to about 1.5 molesof the base, per liter of water being fed.

The water, inorganic base, and the 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin can be fed individually or in anycombination or mixture. However, it is advantageous to feed theinorganic base as an aqueous solution either with or without theco-presence of the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbylhydantoin. In this way, the heat generation that occurs when dissolvinga base in water takes place prior to the introduction of such solutionof aqueous base into the reaction zone. Most preferably, an aqueoussolution of the inorganic base is formed, and to this solution is addedthe 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin. Such aprocedure not only safeguards against excessive heat generation whichmight otherwise adversely affect the 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin, but simplifies the feeding operation andcontrol of the proportions being fed. For best results, it is desirableto employ feed solutions having in the range of about 0.5 to about 2.5moles of the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoinper liter of water. In forming such solutions, use of aqueous alkalinesolutions in the range of about 0.5 to about 5.0 moles of base per literof water is preferred.

In the practice of this invention, halogenation of the 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin is accomplished by use of abrominating agent and a chlorinating agent. Thus use can be made ofbromine, chlorine, bromine chloride, bromine and chlorine, a bromidesalt and chlorine and/or a source of hypochlorite anion, or an organicbrominating or organic chlorinating agent such as N-bromosuccinimide,N-chlorosuccinimide, or pyridinium tribromide, and the like. Of thesehalogenating agents, bromine, chlorine, bromine chloride, bromine andchlorine, a bromide salt and chlorine and/or a source of hypochloriteanion are preferred. Particularly preferred are bromine, chlorine, andmixtures of bromine and chlorine (which will include or consist ofbromine chloride). Highly preferred are bromine and chlorine, especiallywhen the bromine and chlorine are separate feeds. Without desiring to bebound by theoretical considerations, it is believed that the actualspecies which carry out the halogenation in the aqueous reaction mixturecan include, for example, one or more of Br₂, Cl₂, BrCl, OBr^(⊖),OCl^(⊖), Br₃ ^(⊖), BrCl₂ ^(⊖), Cl₃ ^(⊖), Cl^(⊕), and Br^(⊕). Whateverthe actual halogenating species may be, the important thing is to feedto the aqueous reaction mixture suitable brominating agent andchlorinating agent that result in N-halogenation of both nitrogen atomsof the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin beinghalogenated.

If bromine is to be generated in situ, this is best accomplished byreaction between a suitable oxidant, preferably chlorine, and a brominesource such as a water-soluble alkali or alkaline earth metal bromide.

Bromide and/or chloride ions are generated from the brominating agentand/or chlorinating agent, respectively, during the halogenation of the5-hydrocarbyl hydantoin and/or 5.5-dihydrocarbyl hydantoin. The bromideand/or chloride ions can be regenerated in situ to form more brominatingagent and/or chlorinating agent via reaction with a suitable oxidant.Preferred oxidants are the brominating agent and/or chlorinating agentused in this invention.

The proportions of brominating agent and chlorinating agent relative tothe 5-hydrocarbyl hydantoin and/or 5.5-dihydrocarbyl hydantoin should besuch that there are at least about 1.8 atoms of the halogen perhalogenatable amido or imido nitrogen atom to be halogenated.Preferably, there are in the range of about 1.8 to about 3.5 atoms ofthe halogen per halogenatable amido or imido nitrogen atom to behalogenated. Thus in the case of 5-hydrocarbyl hydantoins and/or5,5-dihydrocarbyl hydantoins such as 5,5-dimethylhydantoin theproportions concurrently being fed to the reaction zone are such thatthere are at least about 3.7 atoms of halogen per molecule of5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbylhydantoin. Preferred arein the range of about 3.7 to about 7.0 atoms of halogen per molecule of5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin. Aspreviously noted, under ideal conditions the number of atoms of halogenper amido or imido nitrogen atoms to be halogenated would be preciselythat amount required to produce the desired product without anydeviation whatsoever from the selected stoichiometry. The fact that theforegoing ranges vary from such an ideal ratio simply reflects the factthat under actual large scale plant operating conditions, one canoperate at slightly below the ideal ratio or slightly above the idealratio without material adverse effect relative to the optimum resultsachievable under such conditions. To the extent possible, it ispreferable to operate with a slight excess of the halogen relative tothe 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin in thereaction mixture (i.e., in the range of about 2.0 to about 2.1 atoms ofhalogen per halogenatable amido and imido nitrogen atom to behalogenated) rather than operating continuously in the range of about2.0 to about 1.9. This ensures full halogenation to the extent desiredwithout use of excessive halogen and consequent loss of raw materials.

In the process of this invention, mixtures of halogenated hydantoins arefrequently obtained, in the sense that a mixture ofdifferently-halogenated products, viz. at least two of 1.3-dibromo-,1,3-dichloro-, and N,N′-bromochloro-, and often all three, are presentin the product mixture. The halogenated species which is predominate inthe product can be influenced by controlling the ratios of brominatingagent and chlorinating agent, especially the brominating agent, relativeto the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin duringthe process. In particular, by operating within a pH range of about 2.0to about 5.5 and utilizing a mole ratio between the separate feeds ofbromine or other brominating agent and of chlorine or other chlorinatingagent within the range of about 1:1 to about 1:2.5, new product mixturesof halogenated 5-hydrocarbyl hydantoin and/or halogenated5,5-dihydrocarbyl hydantoin enriched in the 1,3-dibromo-species can beformed. Similarly, when the mole ratio between the separate feeds ofbromine or other brominating agent and of chlorine or other chlorinatingagent within the range of about 1:2.5 to about 1:4, new product mixturesof halogenated 5-hydrocarbyl hydantoin and/or halogenated5,5-dihydrocarbyl hydantoin enriched in the N,N′-bromochloro-species canbe formed. These enriched product mixtures are highly advantageous inthat they are highly cost-effective biocides, especially for watertreatment applications.

Typically the aqueous reaction mixtures of this invention will beformed, in essence, from five types of components, viz., the5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin, thebrominating agent, the chlorinating agent, the inorganic base, andwater. Although it is preferable to minimize the number of components inthe aqueous reaction mixture, it is possible to include one or moreadditional components in such mixtures, provided of course that suchother component(s) cause(s) no material deleterious effect on thereaction or precipitate formation. For example, while not ordinarilyrecommended, it is possible to include certain organic solvents,especially water-miscible organic solvents in the aqueous reactionmixture. Such organic solvent(s) should be in proportions that do notresult in a disproportionately large amount of the desired N-halogenatedhydantoin end product remaining in solution, unless of course thesolvent is to be subsequently removed, for example, by distillation. Atleast one potentially beneficial use of an organic solvent involvesperiodically including one or more organic solvents in the feeds to thereaction zone of the process being operated in a continuous mode inorder to dissolve or dislodge encrustations of precipitate that may havebuilt up in the reaction zone. If an organic solvent is to be includedin the aqueous reaction mixture, besides not unduly affecting theintended N-halogenation reaction adversely, in the usual situation thesolvent should not consume bromine or chlorine. Also, the solvent shouldnot react with the intended N-halogenation product, should not interferewith the in situ generation of bromine (if such is being used), andshould not result in formation of an unworkable or overly pasty orsticky precipitate or, in general have any other material adverse effectupon the conduct or further conduct of the process. A few examples oforganic solvents that may be considered for use areN,N-dimethylformamide, dimethylsulfoxide, one or more C₁₋₄ alkanols,tetrahydrofuran or other saturated ethers, or the like. Therefore,unless expressly stated otherwise, the term “aqueous reaction mixture”as used anywhere in this document, including the claims, does notexclude the presence of one or more organic solvents, provided nomaterial adverse effect upon the reaction or precipitate formation orproduct characteristics is caused by the presence of such solvent(s) inthe amount in which present relative to the total amount of the overallreaction mixture.

When bromine is the brominating agent and/or chlorine is thechlorinating agent, the bromine and/or chlorine should be fed subsurfaceto the aqueous phase in the reaction zone so as to ensure intimatecontact with the 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbylhydantoin being used. When using an alkali metal bromide or an alkalineearth metal bromide and chlorine to generate bromine in situ, thebromide salt can be fed as a separate feed, typically as a watersolution, or it can be fed along with an aqueous solution or slurryformed from the water-soluble base and the 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin. In any such case, the chlorine usedtherewith should be fed subsurface to the aqueous phase in the reactionzone.

Chlorine will typically be fed into the reaction mixture as a liquid,but can be fed in the vapor state, if desired. Bromine can be fed intothe reaction mixture either as a gas or as a liquid. Preferably thebromine is fed in the vapor state subsurface to the liquid phase of theaqueous reaction mixture, and it is desirable to so feed the gaseousbromine in admixture with an inert gas such as nitrogen or argon.

Although it is desirable and preferred to feed diatomic halogens (Cl₂,Br₂, BrCl, or mixtures thereof, and where the Cl₂ itself is being usedas the chlorinating agent and/or is being used in combination with abromine source such as an alkali metal bromide and/or an alkaline earthbromide) subsurface to the liquid phase of the aqueous reaction mixture,other ways of accomplishing the feeding can be used. One other way is tofeed vaporous diatomic halogen into a headspace of a reactor whilespraying aqueous reaction mixture and/or spraying or misting water intointimate contact with such vapors within the reactor. Other ways ofestablishing intimate contact of the diatomic halogen with the remainderof the components from which the aqueous reaction mixtures is formedinclude feeding the halogen as a liquid and/or as a solution into theaqueous reaction mixture, and in such case the halogen can be fed abovethe surface of the aqueous reaction mixture, if desired. In short, thisinvention contemplates the feeding of the halogen in any conceivable waythat accomplishes the objective of bringing the components into intimatecontact with each other so that the intended N-halogenation reactionwill occur. In all cases, agitation of the aqueous reaction mixture isadvantageous.

When bromine and chlorine are used as the brominating agent andchlorinating agent, respectively, they can be fed as separate feeds;separate feeds of bromine and chlorine are preferred. Alternatively,bromine and chlorine can be premixed in any desired proportions wherebythe mixture being fed will contain bromine chloride, and if mixed inmolar proportions other than 1:1, will also contain the halogen used inexcess. In lieu of chlorine, an alkali or alkaline earth metalhypochlorite can be used as the chlorine source. Typically thehypochlorite salt will be fed in the form of an aqueous solution orslurry. However, it is also possible to feed a solid hypochlorite saltsuch as calcium hypochlorite directly into the aqueous reaction mixture.When bromination is desired, the brominating agent feed can be an alkalimetal bromide or an alkaline earth metal bromide, and a source ofchlorine, such as chlorine or an aqueous solution or slurry of an alkalior alkaline earth metal hypochlorite, such as sodium hypochloritesolution, in amounts sufficient to generate bromine in situ. It is alsopossible to feed a solid hypochlorite salt such as calcium hypochloriteto the aqueous reaction mixture in order to generate the bromine insitu. Usually feeds of this type will result in formation of productscontaining both bromine and chlorine in the molecule. While in principleother sources of bromine or chlorine may be used, such as organiccompounds containing loosely bound bromine or chlorine, the use of suchorganic halogenating agents is not preferred as their use can complicateproduct workup and recovery operations. Moreover, such organichalogenating agents tend to be more expensive than such sources asbromine or chlorine, or sodium bromide and chlorine.

When feeding the brominating agent and chlorinating agent into thereactor, best results are achieved when such halogen source isintroduced directly into the body of liquid within the reactor, i.e.,below the surface of the heel or mother liquor when starting up thereaction and below the surface of the aqueous reaction mixture once thereaction has commenced. This will minimize the possibility of some ofthe halogen remaining in the headspace in the reactor and thus notparticipating in the reaction. Also feeds subsurface to the liquid phaseof the reactor contents avoid splattering which can occur when, forexample, liquid bromine strikes the surface of an aqueous mixture.

In this connection, in one of the embodiments of this invention, the5-hydrocarbyl hydantoin and/or the 5,5-dihydrocarbyl hydantoin,inorganic base, brominating agent and chlorinating agent, and water canbe fed either individually and/or in any combination(s) including acombination of all such components. If all such components are fed incombination with each other, this can result in these components comingtogether outside of a typical reactor or reaction vessel. In practicingsuch feeding, the components can initially be brought into contact witheach other in a mixing device in proximity to, but apart from, suchreactor or reaction vessel. Suitable mixing devices include a staticmixer, a conduit (preferably a conduit in which there is turbulentflow), or a jet mixer that produces a high velocity effluent stream. Inall such cases, the mixing device itself in which all of the foregoingcomponents first come into contact with each other is part of thereaction zone.

In a continuous operation, usually and preferably, the effluent from themixing device in which all of the foregoing components are first broughttogether is fed into a larger volume reactor or reaction vesselcontaining a body of the aqueous reaction mixture. Since reaction willbegin essentially as soon as the foregoing components come into contactwith each other, reaction will usually commence in such mixing deviceand will continue in the aqueous reaction mixture in the reactor orreaction vessel, which of course is also part of the reaction zone.Thus, it is desirable to place the mixing device, when using a mixingdevice, in close proximity to the larger volume reactor or reactionvessel and to move the components rapidly into, through, and from themixing device and into a larger volume of aqueous reaction mixture inthe larger reactor or reaction vessel. In this way, the time betweeninitial contact among all of the components and the time when theaqueous reaction mixture comes into contact with a larger volume of theaqueous reaction mixture is kept short enough so that the temperature ofthe reaction mixture at any stage of the operation does not exceed about90° C., and preferably does not exceed about 70° C. If desired, themixing device, if used, can be cooled by indirect heat exchange with acooling or refrigerated fluid.

When using a conduit with turbulent flow therein as the mixing device,such conduit can itself constitute the entire reactor or reaction vesselin a continuous operation. In other words, the reactor or reactionvessel itself can be a tubular reactor of sufficient length and volumefor the reaction and precipitate formation to occur therein.

Preferably, the reactants are concurrently fed into a reaction zonecomposed of at least one reactor in which all of the components—whetherfed individually or in any subcombination(s)—all come together for thefirst time and in which the N-halogenation reaction is initiated andcarried out.

Preferably the pH in the processes of the invention is maintained in therange of about 2.0 to about 8.0. It is particularly preferred to conductthe processes of the invention while maintaining the pH within the rangeof about 2.0 to about 5.5. The processes of this invention can also beconducted at a pH in the range of about 5.5 to about 8.0.

Preferably the concurrent feeds in the processes of this invention arecontinuous feeds. It is also preferable that the feeds are at leastco-feeds—i.e., at least two feeds are utilized, namely (i) an aqueoussolution or slurry formed from an inorganic base and a 5-hydrocarbylhydantoin and/or a 5,5-dihydrocarbyl hydantoin, and (ii) a brominatingagent and a chlorinating agent. However, it is highly preferable toconduct a tri-feed process, where the feeds are (i) an aqueous solutionor slurry formed from an inorganic base and a 5-hydrocarbyl hydantoinand/or a 5,5-dihydrocarbyl hydantoin, (ii) a brominating agent, and(iii) a chlorinating agent. It is also within the scope of thisinvention to conduct other multi-feed processes. Indeed, it is possibleto utilize, for example, both a co-feed and a tri-feed although such anoperation offers no particular advantage. In all cases, the feeds areproportioned such that the nitrogen atoms in the hydantoin molecule aresubstituted by a bromine or chlorine atom. Product formation occursalmost immediately upon the reaction components coming in contact witheach other, and if no solids-containing heel or solids-free motherliquor from a prior reaction is used, precipitation begins shortlythereafter. Once precipitation has commenced, product formation andprecipitation occur continuously or substantially continuously duringthe concurrent feeds. When a solids-containing heel or solids-freemother liquor from a prior reaction is used, the precipitation beginsalmost immediately and continues to occur continuously or substantiallycontinuously during the concurrent feeds. The feeds are proportionedsuch that the pH in the aqueous reaction mixture is maintained orsubstantially continuously maintained in the range of about 2.0 to about8.0, and preferably in the range of about 2.0 to about 5.5. Anotherpreferred pH range is in the range of about 5.5 to about 8.0. Inconducting the process, the materials in the concurrent feeds shouldrapidly come into intimate contact with each other. Thus, it ispreferred to introduce the separate, but concurrent feeds, in close orrelatively close proximity to each other and to provide sufficientagitation to cause such rapid intimate contact and resultant interactionamong the components being fed.

Another highly important feature of this invention is the maintenance ofthe correct pH in the aqueous reaction mixture throughout substantiallythe entire reaction period. Here again, it is possible for slightdepartures to occur in the pH, particularly at the outset of thereaction. Such departures are within the ambit of this inventionprovided of course that no material adverse effects are encountered as aresult of such departures. As noted above, the processes of thisinvention are typically conducted at a pH within the range of about 2.0to about 8.0, and preferably in the range of about 5.5 to about 8.0.However, for best results the pH is most preferably maintained withinthe range of about 2.0 to about 5.5.

A feature of the processes of the invention is ability to influence theaverage particle size of the product. The average particle size appearsat least nominally to vary directly with pH. As the pH increases, theaverage particle size increases; as the pH decreases, the averageparticle size decreases. Thus, when larger average particle sizes aredesired, operation towards the higher end of the pH range isrecommended. Conversely, when a smaller average particle size isdesired, operation at lower pH values is recommended.

To maintain the desired pH in the aqueous reaction mixture, the rates atwhich the feeds of the base, brominating agent, and chlorinating agentplay an important role. In particular, the halogenating agents should befed or generated in situ at a rate sufficient to maintain the pH at thedesired level (e.g., between 2.0 and 8.0, or preferably between 5.5 and8.0, or most preferably between 2.0 and 5.5). In other words, the feedof halogen or the generation of halogen in situ should not be such as todecrease the pH (increase the acidity) of the reaction mixture to a pHsignificantly below about 2.0 for any substantial period of time.Without wishing to be bound by theory, it is believed that thechlorinating agent in particular has a greater impact on the pHLikewise, the base, whether fed singly, as an aqueous solution of base,or in admixture with water and the 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin, should be fed at a rate insufficient toincrease the pH above the desired level (e.g., 8.0 or preferably 5.5).Thus, the feeds should be suitably coordinated so as to maintain the pHof the reaction mixture within the ranges specified herein.

When using bromine or generating bromine in situ and forming a productof white coloration such as a 1,3-dihalo-5,5-dimethylhydantoin, aconvenient way of monitoring the rate of bromine addition or generationis to feed or generate the bromine at a rate such that the color of thereaction mixture is bright yellow to reddish yellow or orange,particularly when bromine is used in an amount nearly equivalent orgreater than the amount of chlorinating agent. The appearance of areaction mixture having a reddish coloration can indicate that anexcessive amount of bromine is present. Other ways of monitoring thehalogen present can be used if desired, such as by use of pH meters,chemical pH indicators, and/or the like. Also the halogen feed orgeneration can be monitored by combinations of any two or more suitablemethods for determining pH, such as a combination of color observationsas described earlier in this paragraph, and use of one or more pHmeters, concurrently or sequentially, or in any other suitable manner.If a combination of two or more ways of measuring pH are used, and if bychance disparate pH measurements result, one should rely upon the methodpreviously determined in actual practice to give the most accurate andreproducible results. Use of carefully calibrated commercially-availablepH meters is currently believed to be one of the most reliable ways ofdetermining pH, but it is not intended that the scope of this inventionbe limited to use of pH meters.

While on the subject of pH control, operations in which the pH driftsabove about 8.5 for any significant length of time are not desirablebecause in general the solubility of the desired product in the aqueousreaction mixture tends to increase under such elevated pH conditions. Infine-tuning an operation utilizing a process of this invention, oneshould strive to provide throughout at least most of the reaction time,a very slight stoichiometric excess of the halogen source relative tothe 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin to ensureachievement of complete halogenation to the desired level. For example,in order to minimize underhalogenation, slightly more than the number ofequivalents of halogen atoms to be introduced into the 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin should be employed, andshould be maintained in the reaction mixture during substantially theentire time the feeds are being carried out.

Still another feature of this invention is that the concurrent feedingof the components enables the maintenance within the reactor of anaqueous reaction mixture of sufficiently low concentration that thereaction can be conducted at elevated temperatures (e.g., 40 to about90° C.) without material decomposition of most 5-hydrocarbyl hydantoinsand/or 5,5-dihydrocarbyl hydantoins, or the N-halogenated productsthereof, depending of course upon the thermal decomposition temperatureof the particular hydantoin being utilized. In sharp contrast,heretofore it has been commonplace to cool the reactor to temperaturesas low as about 5° C. in order to ameliorate the problem ofdecomposition due to presence of excessive base in the system to whichthe halogen is added. Pursuant to this invention, it is preferred whenoperating in a continuous mode to feed the components from which theaqueous reaction mixture is composed in amounts such that the ratio of(i) the volume of the aqueous reaction mixture in liters to (ii) themoles of 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoinbeing fed to the reaction mixture per minute is in the range of about 10to about 100 liters per mole per minute, and preferably in the range ofabout 30 to about 60 liters per mole per minute. Similarly, whenoperating in a batch mode wherein the feeds are to at least one reactor,until the volume of the reaction mixture reaches 50 percent of the totalvolume of the reactor(s), the feeds to the reaction mixture aremaintained such that the ratio of (i) the volume of the reaction mixturein liters to (ii) the moles of the N-halogenatable compound being fed tothe reaction mixture per minute is in the range of about 10 to about 100liters per mole per minute, and preferably in the range of about 20 toabout 80 liters per mole per minute. Then, when the volume of thereaction mixture is 50 percent or more of the total volume of thereactor(s), the feeds to the reaction mixture are such that the ratio of(i) the volume of the reaction mixture in liters to (ii) the moles ofthe 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin being fedto the reaction mixture per minute is in the range of about 30 to about60 liters per mole per minute. By operating a continuous, semi-batch, orbatch process using the foregoing ratios, the 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin and the N-halogenated derivative(s)thereof are less susceptible to thermal decomposition from the heat ofreaction.

The processes of this invention can be carried out in various ways, suchas in a batch mode, in a semi-batch mode, or, preferably, in acontinuous mode. When conducting a continuous operation, it is desirableto design the operation such that the average residence time fallswithin the range of about 15 to about 100 minutes, and preferably in therange of about 30 to about 60 minutes. As with all of the numericalranges given herein, departures therefrom are permissible wheneverdeemed necessary or desirable, provided only that such departures do notmaterially detract from the efficacy and effectiveness of the process.

In conducting the processes of this invention, the reaction temperaturescan be varied within a reasonable range. Typically, the reactiontemperature will fall within the range of about 10 to about 90° C.although under some conditions departures from this temperature rangemay prove acceptable under particular circumstances. Of ten timestemperatures in the range of about 20 to about 80° C. or 90° C. will befound more efficacious. However, temperatures within the range of about30 to about 70° C. are generally preferred inasmuch as reactionsperformed at these temperatures tend to produce products in the highestyields. It is most preferred to perform the reaction at temperatures inthe range of about 40 to about 60° C., especially when utilizing ahydantoin such as 5,5-dimethylhydantoin, and bromine as the brominatingagent. Temperatures in the range of about 40 to about 60° C. are mostpreferred because operations conducted within this range produce productin high yield at fast reaction rates and in the most cost-effectivemanner. When conducting the N-halogenation reaction at temperaturesabove the boiling temperature of the halogen being fed, it is desirableto feed the halogen subsurface to the liquid phase of the aqueousreaction mixture. In such a case, it is particularly desirable to feedthe halogen diluted with an inert gas.

Yet another feature of this invention is the fact that the processes canbe conducted adiabatically without material reduction in reactorthroughput. Thus even when the process is conducted without adding heatenergy into the reaction mixture and without recourse to refrigeration,or use of a flowing liquid heat transfer agent, or other ways of cooling(except possibly for normal unassisted heat transfer through the reactorwalls to the surrounding atmosphere), the heat buildup from theexothermic reaction can be readily controlled without materiallyreducing feed rates. Such control can be achieved by maintaining adilute aqueous reaction mixture, e.g., by operating a continuous,semi-batch, or batch process using the ratios of volume of reactionmixture to moles of N-halogenatable compound being fed per minute asdescribed hereinabove. Despite such dilution, the reaction andprecipitate formation nonetheless can proceed rapidly under suchadiabatic conditions.

Even though adiabatic operation is possible, when conducting theprocesses of this invention, especially in a continuous mode, it ispreferred to utilize a flow of cooling water or other heat exchangeliquid for indirect heat exchange with the reactor contents to ensuremaintenance of steady-state temperature conditions in the reactionmixture. If desired, however, the processes of this invention can beconducted using refrigeration.

The processes of this invention can be conducted in any of a variety ofmodes of operation. For example, the processes can be carried out in abatch mode, in a semi-batch mode with constant overflow, in a semi-batchmode without overflow, or in a continuous mode. The engineering detailsconcerning such modes of process operation are well known in the art, aswitness, for example, Perry's Chemical Engineer's Handbook, 4th Edition,McGraw-Hill, copyright 1963.

Because of the short reaction and precipitation times which are featuresof processes of this invention, it is possible, indeed preferred, toconduct the processes in a semi-batch mode, and more preferably in acontinuous mode. This in itself is a rarity, as the literature onhalogenation of 5-hydrocarbyl and 5,5-dihydrocarbyl hydantoins isreplete with teachings involving only batch operations. In thecontinuous mode, reactor size can be substantially reduced without aloss in product output.

When conducted in a batch mode or when initiating a semi-batch orcontinuous process, it is preferred, although not required, to initiallycharge to the empty reactor either a solids-containing heel of areaction mixture from a prior reaction in which the product to be formedhad been formed or a solids-free mother liquor from such a priorreaction. Such heel or mother liquor typically has a pH in the range ofabout 6 to about 7, and usually contains up to 2 wt % of the productand/or a precursor thereof. Then the concurrent, suitably-proportionedfeeds are initiated, typically at room temperature, and precipitateformation commences almost immediately, and in any event within a fewminutes. In a batch operation, the feeds are typically continued untilthe reactor has been, or until the reactors have been, filled to thedesired level. Usually at this point, the feeds are terminated, and thehalogenated product which has formed and precipitated is recovered,typically by filtration, centrifugation, or decantation. Since thereaction is exothermic and rapid, long ride periods at the end of thefeeding are normally unnecessary.

Observations to date while conducting the processes of this inventionindicate that the reaction and precipitate formation are extremely fast.When no solids-containing heel or solids-free mother liquor from a priorreaction is used, the slight delay in the commencement of precipitateformation at the beginning of the concurrent feeds is believed to besimply the time required for the aqueous reaction mixture to becomesuitably saturated with the product. When a solids-containing heel orsolids-free mother liquor from a prior reaction is used, little or nodelay occurs in the commencement of precipitate formation at thebeginning of the concurrent feeds. Because the rapidity of the reaction,upon termination of the concurrent feeds, precipitation may continue tooccur in the aqueous reaction mixture for only a very short period oftime.

Another feature of this invention is that the co-product is a relativelypure aqueous saline solution, thus minimizing environmental and disposalproblems. Moreover, when using bromine as the halogen and an alkali oralkaline earth metal salt or oxide as the base in the process, theresultant co-product is an aqueous solution of alkali or alkaline earthmetal bromide from which bromine can be recovered by oxidation ofbromide ion to elemental bromine, for example by treatment of thesolution with chlorine.

It can be seen therefore, whether operating in a batch mode, asemi-batch mode, or in a continuous mode, the initiation of the reactionwith the utilization of a heel or mother liquor enables the more rapidachievement of efficient, steady-state operation than if a heel ormother liquor is not employed.

In a batch operation the aqueous reaction mixture is largely created andincreased in volume by the feeds. In operations conducted in the batch,semi-batch, or continuous mode, it is highly desirable to vigorouslyagitate the reaction mixture to ensure thorough mixing of the reactioncomponents.

The components of the reaction mixture should be agitated to asufficient extent so as to avoid localized concentrations of eitherhalogen or base. Thus, for example, in laboratory scale operations,stirring rates in the range of about 300-600 rpm have been founddesirable for achieving good mixing within the reaction vessel. In plantscale operations use of a continuously stirred reactor is thusrecommended.

In typical, properly conducted batch operations, during at least about80% of the period of time the separate feeds are being fed concurrently,and preferably during at least about 90% of the foregoing period oftime, precipitate is being formed that typically is essentially pureproduct (e.g., with a purity of at least about 80%, usually at leastabout 90%, and often as much as about 97% purity). Also, typically thedesired product is formed in a yield of at least about 80%, and often ashigh as 94% or more, based on the amount of the 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin used in the reaction. In typical,properly conducted continuous operations, once steady-state operationhas been achieved, precipitate is continuously being formed that (a)also typically has a purity of at least about 96%, and often as much as99.9%, and (b) typically is formed in a substantially continuous yieldof at least about 85% based on the amount of the 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin being fed as a reactant in theprocess.

If the reaction is performed in a reactor of sufficient size, the volumeof the reactor contents can be cycled between predetermined low and highvolumes with initiation of rapid draining when the volume reaches thehigh volume of reactor contents, and with discontinued draining once thevolume reaches the low volume of reactor contents. However, it ispreferred to conduct the process so that the volume of the contents ofthe reactor and the volume of the precipitate and portion of thereaction mixture removed from the reactor are equal or substantiallyequal whereby the volume of reactor contents remains constant orsubstantially constant. In this way, reactors with smaller volumes canbe employed.

When operating in a continuous mode and once the continuous feeds havebeen initiated, the feeds may be adjusted in fine tuning the operationso as to establish and maintain the desired operating conditions for thesteady-state operation. Such operation typically can be conductedwithout mishap for long periods of time before shutdown, e.g., for plantmaintenance.

Thus, once steady-state conditions have been achieved in a continuousreactor, the separate feeds can be fed in appropriate proportions on acontinuous basis, and the reactor contents maintained under theappropriate reaction conditions for virtually unlimited periods of time.Concurrently, a portion of the reaction mixture including precipitate(which mixture typically is in the form of a slurry) is being removed,usually and preferably continuously, from the reaction mixture so thatthe volume of the contents of the reactor remains more or less constant.

From the foregoing it can be seen that this invention involves aninterrelationship among controllable reaction variables which result inthe production of high quality products in high yield in rapidreactions. Thus, this invention features, inter alia, concurrent feedsof the reaction components with specified control of pH by means of feedrates. In preferred embodiments, adjustment and control of temperatureenables rapid formation of product in high yield. Also, utilization ofreaction mixtures in highly diluted conditions contributes materially,in preferred embodiments, to high yields and allows greater flexibilityin operating temperatures. Moreover, the rapid precipitate formationunder steady-state conditions makes possible the use of short residencetimes in continuous operations, and thus contributes materially toimproved plant throughput.

It is to be noted that when the term “subsurface” is used anywhere inthis document, including the claims, the term does not denote that theremust be a headspace in the reaction zone. For example, if the reactionzone is completely filled with the aqueous reaction mixture (with equalrates of incoming and outgoing flows), the term “subsurface” means inthis case that the substance being fed subsurface is being fed directlyinto the body of the aqueous reaction mixture, the surface thereof beingdefined by the enclosing walls of the reaction zone.

The use of the term “concurrent” does not exclude the possibility ofinconsequential interruptions taking place during the feeds. Nor doesthis term imply that the feeds must start at exactly the same moment intime. In the case of a co-feed process, the two feeds can be initiatedwith an interval of time between such initiation as long as the intervalis sufficiently short as to cause no material adverse effect upon theoverall process. Likewise in the case of a tri-feed or multi-feedoperation, there may be one or two different time intervals between oramong the respective feeds, again provided that the time intervals areof sufficiently short duration to cause no material adverse effect uponthe overall process.

The processes of this invention, whether performed in a batch mode,semi-batch mode, or continuous mode, are preferably conducted so thatsuch things as the feeds, reaction, precipitate formation, andmaintenance of specified pH occur “continuously” during the reaction.However, it cannot be stressed strongly enough that one must not gainthe impression that inconsequential interruption in one or more of suchthings cannot occur. Interruptions which do not materially affect theconduct of the process are not excluded from the scope of thisinvention. To safeguard against hypertechnical legalistic wordinterpretation, it has been deemed prudent to employ terms such as“substantially continuously” in describing this invention. But whateverthe terms used, the process should be conducted as one of ordinary skillin the art would carry out the processes after a thorough, unbiasedreading of this entire disclosure and in keeping with the spirit of theinvention gained from such a reading.

An important feature of this invention is the concurrent feeding of theseparate feeds referred to above. It is again to be emphasized that theterm “concurrent” does not imply that the feeds must start at exactlythe same time or that they must stop at exactly the same period of time.Rather, the term is used in the sense that during substantially theentire reaction period, the designated feeds are being maintained. Itshould also be understood that while these concurrent feeds arepreferably continuous concurrent feeds, slight interruptions in a feedare acceptable provided that the duration of the interruption issufficiently small as to cause no material disruption in the reaction.Thus as used herein, the terms “concurrent” and “continuous” should beunderstood to embrace the minor departures just referred to. Naturally,those skilled in the art will strive to utilize the concurrent feedswith as little nonconcurrence as possible. Likewise, those skilled inthe art will of course seek to maintain the continuous feeds with as fewinterruptions as possible under the given circumstances in which theoperation is being conducted. However, because the reaction mixtures aregenerally capable of standing for days without material change incomposition, it is possible to interrupt an uncompleted operation(whether conducted in a batch mode, in a semi-batch mode, or in acontinuous mode) for long periods of time should this become necessary.

The products of the processes of the invention are halogenated5-hydrocarbyl hydantoins and halogenated 5,5-dihydrocarbyl hydantoins,and are obtained in high yield and purity from the reactor without needfor further purification. As mentioned above, the average particle sizeof the products of the processes of this invention can be influenced bycontrolling the pH during the process. Typically, mixtures ofhalogenated hydantoins are obtained, in the sense of having a mixture ofdifferently-halogenated products, viz. at least two of dibromo-,dichloro-, and bromochloro-, and frequently all three, being present inthe product mixture. As noted above, which of the halogenated species(dibromo-, dichloro-, or bromochloro-), is predominate in the productcan be influenced by controlling the ratios of brominating agent andchlorinating agent, especially the brominating agent, relative to the5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin.

The compositions of the invention, which can be produced by theprocesses of this invention, are comprised of halogenated 5-hydrocarbylhydantoins and halogenated 5,5-dihydrocarbyl hydantoins, and arenormally a mixture of differently-halogenated products. The halogenated5-hydrocarbyl hydantoins and halogenated 5,5-dihydrocarbyl hydantoinsare 1,3-dibromo-, 1,3-dichloro-, and/or N,N′-bromochloro-derivatives of5-hydrocarbyl hydantoins and 5,5-dihydrocarbyl hydantoins. Halogenated5,5-dihydrocarbyl hydantoins are preferred. Particularly preferredhalogenated hydantoins are halogenated 5-alkyl and halogenated5,5-dialkyl hydantoins, especially those in which each alkyl groupcontains up to about 6 carbon atoms. Still more preferred arehalogenated 5,5-dialkyl hydantoins in which each alkyl group contains,independently, up to 3 carbon atoms. Especially preferred arehalogenated 5,5-dimethylhydantoins.

As just described for the products of this invention, the compositionsof this invention are usually comprised of a mixture ofdifferently-halogenated products. In preferred compositions, thedibromo- or the bromochloro-species is predominate. In compositions ofthe invention in which the bromochloro-species is predominate, it ispreferred that the bromochloro-species is at least about 40% of thecomposition, while the dibromo-species is at least about 30% of thecomposition. Compositions of this invention in which thebromochloro-species is predominant preferably have an average particlesize of at least about 50 microns, and more preferably at least about 75microns. Particularly preferred compositions in which the bromochlorospecies is predominate are comprised of at least about 40%bromochloro-species and at least about 30% dibromo-species, and have anaverage particle size of at least about 50 microns. More preferably, thedibromo-species is predominate. Particularly preferred compositions ofthis invention in which the dibromo-species is predominate are those inwhich the dibromo-species comprises at least about 80% of thecomposition; especially preferred are such compositions in which thedibromo-species comprises at least about 90% of the composition.Compositions of this invention in which the dibromo-species ispredominant preferably have an average particle size of at least about50 microns, and more preferably at least about 100 microns. Highlypreferred compositions are those in which the dibromo species comprisesat least about 80% of the composition, and have an average particle sizeof at least about 50 microns, especially when the hydantoin is ahalogenated 5,5-dimethylhydantoin.

As can be readily seen from the Examples hereinafter, this inventionmakes possible the provision of halogenated 5-hydrocarbyl hydantoins andhalogenated 5,5-dihydrocarbyl hydantoins in high yield and purity. Infact, mixtures of halogenated hydantoins in which the dibromohydantoinis the predominate species have been obtained by use of the presentprocess technology. Moreover, the 1,3-dihalo-5,5-dimethylhydantoinsproduced by processes of this invention are devoid of traces oforganohalide solvent residues inasmuch as these products are formed inthe absence of any halogenated organic solvent such as methylenechloride.

In the Examples, abbreviations for the hydantoins are used. DMH standsfor 5,5-dimethylhydantoin; DBDMH stands for1,3-dibromo-5,5-dimethylhydantoin; BCDMH stands forN,N′-bromochloro-5,5-dimethylhydantoin; and DCDMH stands for1,3-dichloro-5,5-dimethylhydantoin. These abbreviations may also appearelsewhere in this document, and have the same meaning as just set forth.

The following Examples are presented to illustrate the practice of, andadvantages made possible by, this invention. These Examples are notintended to limit, and should not be construed as limiting, the scope ofthis invention to the particular operations or conditions describedtherein. In Examples 1-7 liquid bromine (Aldrich) is fed subsurface intothe reaction mixture. Both liquid bromine and the DMH/NaOH solutions arepumped into the reactor using Cole-Parmer Masterflex computerized drive(2 pump heads, 1 to 60 rpm) and Easy-Load pump head. For bromine, Vitontubing is used in connection with Teflon. For the DMH/NaOH solution,C-Flex tubing is used. Chlorine gas is bubbled into the reaction slurry,also subsurface. The NaOH solutions are made using regular tap water,then allowed to cool down to room temperature before adding the DMH tomake a clear solution.

For the continuous run (Example 7), fractions (residence times) werecollected manually such that the reactor level was maintained constant.Each fraction (typically 500 mL) was filtered and the original filtratewas analyzed within days. The solid was washed with tap water. Dryingwas carried out in filtration funnel under nitrogen or in vacuum oven at˜55° C. Co-feeding the reagents was monitored by use of a pH meter. Thestarting DMH (97%) was purchased from Aldrich. All reactions werecarried out in a 4-neck 1-L jacketed glass flask. The reactor wasequipped with a mechanical stirrer, a thermocouple, and a pH meter. Theresulting reaction slurry was collected manually and intermittently fromthe bottom of the reactor. Each fraction was collected in a 500 mLflask.

The following analytical procedures were used in connection withExamples 1-7: DBDMH or BCDMH particle size was determined by use ofCoulter LS particle size analyzer with typical run time of 1 minute persample. The purity of the bromine content of both solid DBDMH and itsfiltrate was determined by iodometric titration. Proton NMR spectra wereobtained in dry CD₂Cl₂ on a Bruker/GE Omega 400WB. The spectra werebroadband C-13 decoupled to eliminate ¹³C satellites. The residualproton resonance of the deuterated solvent was assigned to 5.32 ppm.Normalized wt % of the brominated and chlorinated species werecalculated. The BCDMH was analyzed by ¹H-NMR, in dried deuteratedmethylene chloride, to determine the isomers ratio. Each chemical shiftrepresented the gem dimethyl group (6 H, s) in the hydantoin molecule.

Example 1

Batch Trifeed Operation at 53° C., pH˜6-8

Into a 4-neck 1-L jacketed glass flask equipped with a mechanicalstirrer (400 rpm), a thermocouple, and a pH meter and heated via acirculating bath, are charged a 200 mL heel of 5% NaCl solution. Asolution of 5,5-dimethylhydantoin (DMH) is prepared by dissolving 44.5 g(1.11 mol) of NaOH in 339 g of water, and after cooling to roomtemperature, DMH (70.4 g, 0.549 mol) is added. The DMH solution is fedat 10.0 mL/min rate while the bromine is fed at ˜0.80 mL/min subsurface.Chlorine is also co-fed subsurface in a rate such that the pH of themixture ranges between 6 and 8. The reaction temperature is about 53° C.When the DMH feed ends, about 86.4 g of bromine is consumed (0.540 mol,˜98% of the bromine needed for total DMH bromination). The total amountof chlorine consumed is in the vicinity of about 0.8 mol. During the 44minutes of the trifeed, a yellow to orange color persisted on the top ofthe reaction slurry. After filtering and washing the product with water,an off white solid (149.4 g, ˜96% yield) was obtained. Filtrate analysisindicated the presence of ˜0.2 wt. % of active bromine, ˜0.3 wt % ofbromide, and ˜7.2% of chloride. Analytical data are summarized inTable 1. DBDMH was obtained in >98% purity with no dichloro species andonly ˜1 wt % of BCDMH.

Example 2

Batch Trifeed Operation 52° C., pH˜5-7

The reagents are prepared as in Example 1 and the process is carried outsimilarly except that the pH of the slurry is kept between 5-7 (mostlybetween 5-6) by faster bubbling of the chlorine. About 87.7 g of bromineis consumed (0.548 mol, which is ˜99% of the bromine needed for totalDMH bromination) during the 38 minutes of the trifeed. Chlorine addedduring the trifeed is ˜40.5 g (0.571 mol). The reaction slurry is mostlyyellow, but at the end of addition a reddish color appears on thereaction surface and the slurry turns yellow when it reaches roomtemperature. After work up and drying, an off white solid (149.2 g,˜95%) is obtained. Analytical data are summarized in Table 1. DBDMHpurity is ˜92% with formation of 7 wt % of BCDMH and a trace of the1,3-dichloro species.

Example 3

Batch Trifeed at 53° C., pH˜5-6

The reagents were prepared as in Example 1 and the reaction was carriedout similarly except that the pH of the slurry was maintained between5-6 (mostly between 5-5.5) by faster bubbling of the chlorine. About87.7 g bromine was consumed (0.548 mol, ˜99% of the bromine needed fortotal DMH bromination) during the 38 minutes of the trifeed. Chlorineadded during the trifeed was ˜39 g (0.549 mol). A red orange colorpersisted on the surface of the reaction slurry. At the end of addition,the reaction filtrate was totally colorless. After work up and drying,an off white solid (149.8 g, ˜96% yield) was obtained. Filtrate analysisindicated the presence of 0.2 wt % active bromine, ˜0.6 bromide, and˜6.9% chloride. Analytical data are summarized in Table 1. DBDMH wasobtained in 98% purity with no dichloro species, and only 1.7 wt % ofBCDMH was present.

Example 4

Batch Trifeed at 44° C., pH˜2-5

The reagents were prepared as in Example 1 and the reaction was carriedout similarly except that the temperature was maintained at 44° C. andthe pH of the slurry was maintained between 1.7-5.5 by faster bubblingof the chlorine. About 84.2 g bromine was consumed (0.527 mol, ˜96% ofthe bromine needed for total DMH bromination) during the 41 minutes ofthe trifeed. Chlorine added during the trifeed was 74.2 g (1.046 mol).During the trifeed, an orange-yellow color persisted and a reddish coloraccumulated on the top of the slurry at the end of the additions. Afterwork up and drying, a white powder (142.7 g, ˜92% yield) was obtained.Analytical data are summarized in Table 1. DBDMH was obtained in ˜82%purity with formation of 16 wt % of BCDMH and only ˜1% dichloro species.

TABLE 1 Isomer Ex. Br₂ Isolated g Distribution No. Temp. pH added, g(yield %) APS* DB:BC:DC** 1 53° C. 6-8 86.4 149.4 (>96) 251.798.6:01.2:0.0 2 53° C. 5-7 87.7 149.2 (>95) 124.0 92.2:07.4:0.1 3 53° C.5-6 87.7 149.8 (>96) 98.4 98.0:01.7:0.0 4 44° C. 2-5 84.3 142.7 (~92)10.5 82.1:16.4:1.0 *APS refers to average particle size in microns.**DB:BC:DC refers to DBDMH:BCDMH:DCDMH

Example 5

Batch Trifeed Operation at 53° C., pH 6-7

Into a heated 4-neck 1-L jacketed glass flask equipped with a mechanicalstirrer (400-475 rpm), a thermocouple, and a pH meter was charged 200 mLheel of 5% NaCl solution. DMH solution was prepared by dissolving 44.5 g(1.11 mol) NaOH in 339 g water, and after cooling to room temperatureDMH (70.4 g, 0.549 mol) was added producing ˜400 mL homogeneoussolution, ˜1.37 M (Note that here the final halogenated DMHconcentration is ˜0.9 M since a heel of ˜200 mL was used. This may inpart explain the darker color of later residence times of continuousExample 7 below, while the color of the initial residence times arenoticeably whiter). The DMH solution was fed at 10.0 mL/min rate whilethe bromine was fed at ˜0.40 mL/min subsurface. Chlorine was bubbledsubsurface at a rate such that the pH of the reaction mixture rangedbetween 6 and 7 and the reaction temperature was stabilized around 53°C. When the DMH feed ended, about 43.7 g bromine was consumed (0.273mol) along with 66.6 g chlorine (˜0.939 mol, i.e. added chlorine tobromine 3.4:1 or ˜13% excess chlorine is used). During the 37 minutes ofthe trifeed, a lemon yellow color atop the slurry persisted and noreddish color accumulated on the top of the slurry as was observed inExamples 1-4. After slurry filtration (36° C.), washing with water (500mL), and drying under nitrogen overnight, a very white solid (YI 6.75)was obtained (118.3 g, ˜90% yield). Upon standing overnight, thecolorless filtrate was found to contain few floating crystals indicatingthat filtration should be carried out at or below room temperature.Isomer distribution of the isolated BCDMH and other analytical data aresummarized in Tables 2 and 3. The isomers distribution is similar tocommercial samples.

Example 6

Batch Trifeed Operation at 53° C., pH˜7

The reagents were prepared as in Example 5. Reaction was carried outsimilarly except the bromine feed rate was reduced by ˜12% to 0.35mL/min rate in an attempt to influence the isomers distribution whileconducting the reaction at a pH around 7.0 by modifying the chlorinebubbling rate. About 42.5 g bromine was consumed (0.266 mol) and 53.5 gchlorine (˜0.75 mol, i.e. added chlorine to bromine 2.8:1 or ˜93% of therequired chlorine) were added.

During the 41 minutes of the trifeed, the reaction slurry was almostcolorless with no apparent halogen coloration. After slurry filtration(30° C.), washing with water (700 mL), and drying under nitrogenovernight, a white solid (YI 7.60) was obtained (105.1 g, ˜80% yield).Isomers distribution of the isolated BCDMH and other analytical data aresummarized in Tables 2 and 3. Higher than expected DBDMH ratio wasobtained, apparently as a result of operating above pH 6.0 and additionof less than required stoichiometric chlorine.

In Table 2, the following abbreviations are used:

-   -   BC refers to N,N′-bromochloro-5,5-dimethylhydantoin;    -   DB refers to 1,3-dibromo-5,5-dimethylhydantoin;    -   DC refers to 1,3-dichloro-5,5-dimethylhydantoin;    -   MB refers to N- and/or N′-monobromo-5,5-dimethylhydantoin;    -   MC refers to N- and/or N′-monochloro-5,5-dimethylhydantoin;    -   YI refers to Yellowness Index;

APS refers to average particle size in microns.

TABLE 2 Isomers Distribution* and Properties Ex. No. BC DB DC MB MC YIpH APS Yield % 5 50.0 33.8 16.0 0.1 nd 6.7 6-7 101 ~90 6 47.9 38.5 13.40.2 0.1 7.6 7 91 ~80 *All ratios were determined by ¹H-NMR in dryCD₂Cl₂, immediately after dissolving the solid.

TABLE 3 Wet Analysis of Trifeed Runs of Examples 5 and 6 as Related toReactants Assay Example 5 Example 6 Wt % Active Bromine 65.1 64.5Bromine 36 38.7 Chlorine 13 11.3 Nitrogen 10.9 8.2 pH at 5 minutes 5.635.64 pH at 10 minutes 4.93 5.25 pH at 15 minutes 4.55 4.78 BromineReacted, g 43.7 42.5 (0.273 mol) (0.266 mol) Chlorine Used, g 66.6 53.5(0.94 mol)  (0.75 mol)  Product Collected, g 118.3 105.1

The weight of added chlorine in Examples 5 and 6 was determined bycalculating the weight difference before and after the trifeed processbegins. From the results shown in Table 3 it was concluded that betterchlorine control and continuous monitoring of chlorine weight wouldenable more precise achievement of a preselected ratio of intendedproducts in the mixture formed in the reaction. Generally speaking, thetotal chlorine needed for approximately ˜0.55 mol DMH=0.55 mol Cl₂ or39.0 g in addition to enough chlorine to oxidize 0.266 mol of bromide or18.9 g, i.e., a total of at least 57.9 g of chlorine.

Examples 1-6 above were conducted as batch operations. Example 7hereinafter was conducted as a continuous process. Some of the mainadvantages of operating the continuous process are continuous removal ofgenerated heat along with product in this exothermic bromination/in-situoxidation/chlorination reaction. The benefit of co-feeding DMH/NaOH withthe separate feeds of the halogens is the minimization of concentrationbuildup of any reagent at any given time. This allows a faster reactionrate at elevated temperatures and resulting product (e.g., BCDMH andDBDMH) precipitates out of solution almost immediately and steadily in acrystalline form. It becomes apparent that within the reactor that thereaction mixture is mostly product slurry and only very limitedconcentrations of halogens, DMH, or NaOH are present. Typically, onlyminimum amount of bromide is present and essentially no bromine. Therates of the feeds can be adjusted so that approximately stoichiometricamounts (i.e., theoretical amounts for producing BCDMH) are present(NaOH:DMH:Br₂:Cl₂=2.0:1.0:0.5:1.5) and all are present in smallconcentrations. As will be seen, the theoretical amounts for producingBCDMH actually resulted in production of a product enriched in bothBCDMH and in DBDMH.

Example 7

Continuous Trifeed Operation at 53° C., pH˜5.8-6.8

In this continuous tri-feed process, six fractions (i.e., continuousoperation equivalent to six batch residence times) were collectedmanually at a rate such that the reactor level was constant. Fractions 1and 2 were combined. Fractions 4 and 5 were also combined. Final reactorcontent was labeled as fraction # 6. Each fraction (500 mL) was filteredand the original filtrates were independently analyzed. The solids werewashed with tap water. Drying was carried out in filtration funnel undernitrogen or in vacuum oven at ˜60° C. Solids fractions obtained werealso independently analyzed by iodometric titration, proton-NMR and forparticle size measurements.

Into a 4-neck 1-L jacketed glass flask equipped with a mechanicalstirrer (400 rpm mixing rate), a thermocouple, and a pH meter wascharged 500 mL heel composed of 300 mL water and 200 mL filtrate of aprevious batch run (either from Example 5 or 6). The reactor temperaturewas kept constant by using a circulating heating bath. DMH feed solutionwas prepared by dissolving 222.5 g of NaOH (5.56 mol) in 1690 g ofwater, and after cooling to room temperature the DMH (352 g, 2.74 mol)was added producing about two liters of a homogeneous solution, i.e.,1.37 M solution. (Note that the concentration of this run is similar tothose of Examples 5 and 6. It is ˜25% more concentrated, compared to DMHfeed used in Examples 1 and 2, in which ˜1.1 M DMH solution was co-fedwith bromine, producing white DBDMH solid).

The DMH solution was fed at 10.0 mL/min rate while feeding liquidbromine at ˜0.39 mL/min subsurface. Chlorine was bubbled also subsurfaceat a rate such that the pH or the reaction mixture ranged between 5.8and 6.8 and the reaction temperature was stabilized around 53° C. WhenDMH feed ended, about 238.1 g of bromine (1.489 mol) was consumed (or2.97 moles of bromonium ions, assuming all bromides are oxidized tobromine) and 276.5 g of chlorine (˜3.89 mol, i.e., overall, addedchlorine to bromine was 2.6:1 which means about 15% less chlorine isused due to the difficulty of maintaining precise gas control at thescale of operation being used. This also explains the greater DBDMHisomer distribution ratio that was achieved. The average residence timeof each fraction was ˜30 min. Each fraction was treated as a separatereaction mixture and was washed with an approximately equal volumewater. After drying in a vacuum oven overnight, a total of 610 g ofsolid (˜91% yield based on DMH and added bromine) was collected.Analyses of all the fractions (1-6) are summarized in Tables 4 and 5.Filtrates of fractions 3-6 were also examined by iodometric titration.The active halogen loss was minimal in the filtrates and indicates mostof bromide was oxidized by chlorine, as can be seen in Table 6.

TABLE 4 Continuous Trifeed Process (With Fractions 1-6) Residence IsomerDistribution APS, Time* DB:BC:DC Color (YI) microns 1 + 2 40.9:44.7:14.27.05 72 3 44.1:44.4:11.4 8.55 120 4 + 5 39.6:46.3:13.8 8.86 174 634.8:47.1:17.8 7.93 73 *Each Residence time - or a combination offractions - was treated as an independent reaction and separatelyanalyzed.

TABLE 5 Analysis of Solid Fractions 1-6 Assay 1 + 2 3 4 + 5 6 Wt %Active Bromine 64.7 63.9 64.7 65.6 Bromine 38.5 40.6 38.7 36.4 Chlorine11.3 10.1 11.3 12.7 Nitrogen 10.8 10.7 10.7 11.1 pH at 5 min. 5.78 5.755.63 5.62 pH at 10 min. 5.40 5.43 5.28 5.18 pH at 15 min. 4.99 5.10 4.904.75

TABLE 6 Analysis of Continuous Trifeed Filtrates (of residence times3-6) Assay 3 4 + 5 6 Wt % Active Bromine 0.29 0.28 0.42 Bromine 0.2 0.20.2 Chlorine 8.7 8.6 7.0

The products of the above Examples which are product mixtures ofhalogenated 5,5-dimethylhydantoins enriched in the 1,3-dibromo-speciesor the N,N′-bromochloro-species constitute new, preferred highlycost-effective biocidal compositions of this invention.

It can be seen from the foregoing experimental results of the Examplesthat the new process technology of this invention makes possible controlor regulation of the halogenation of a single 5-hydrocarbyl hydantoin or5,5-dihydrocarbyl hydantoin (e.g., 5,5-dimethylhydantoin) to produce areaction product containing a mixture of the 1,3-dibromohydantointogether with the N,N′-bromochlorohydantoin and optionally the1,3-dichlorohydantoin in which proportions of these halogenated productsin the mixture can be controlled so as to be within predeterminedexperimental limits. The process technology can also be applied tomixtures of 5-hydrocarbyl hydantoins and/or 5,5-dihydrocarbyl hydantoinsas the starting material, and in this case more complicated mixtures ofend products will be formed as the reaction product. Thus, for example,if using a mixture of two or more 5,5-dialkylhydantoins as the startingmaterial, it is desirable to use a mixture of known composition.

Some exemplary embodiments of this invention are as follows:

A process for the N-halogenation of at least one 5-hydrocarbyl hydantoinand/or at least one 5,5-dihydrocarbyl hydantoin, which process comprisesconcurrently feeding into a reaction zone (i) water, inorganic base, and5,5-dimethylhydantoin, these being fed separately and/or in anycombination(s), (ii) a separate feed of a brominating agent, and (iii) aseparate feed of a chlorinating agent, in proportions such that duringall or substantially all of the time the concurrent feeding is occurringhalogenation of both nitrogen atoms of said 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin occurs and resultant halogenatedproduct precipitates in the liquid phase of an aqueous reaction mixture,and in which the pH of said liquid phase is continuously orsubstantially continuously maintained in the range of about 2.0 to about8.0 during all or substantially all of the time the concurrent feedingis occurring:

-   -   wherein the temperature of said aqueous reaction mixture is in        the range of about 40 to about 60° C.; or    -   wherein the proportions of water, inorganic base, and        5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin being        fed are such that:        -   A) where the inorganic base has a monovalent cation, there            are from about 0.5 to about 2.5 moles of 5-hydrocarbyl            hydantoin and/or 5,5-dihydrocarbyl hydantoin and from about            1.0 to about 5.0 moles of the base, per liter of water; and        -   B) where the base has a divalent cation, there are about 0.5            to about 2.5 moles of 5-hydrocarbyl hydantoin and/or            5,5-dihydrocarbyl hydantoin and from about 0.5 to about 2.5            moles of the base, per liter of water; or    -   wherein said pH is in the range of about 2.0 to about 5.5, and        wherein the separate feeds of brominating agent and of        chlorinating agent are proportioned such that a mole ratio of        brominating agent to chlorinating agent is within the range of        about 1:1 to about 1:2.5; or    -   wherein said pH is in the range of about 2.0 to about 5.5, and        wherein the separate feeds of brominating agent and of        chlorinating agent are proportioned such that a mole ratio of        brominating agent to chlorinating agent is within the range of        about 1:2.5 to about 1:4.

A composition of matter which comprises a halogenated 5-hydrocarbylhydantoin and/or a halogenated 5,5-dihydrocarbyl hydantoin, which is amixture of the 1,3-dibromo-, 1,3-dichloro-, and/orN,N′-bromochloro-species of the halogenated hydantoin:

-   -   wherein the N,N′-bromochloro-species is predominate, wherein the        N,N′-bromochloro-species comprises at least about 40% of the        composition, while the 1,3-dibromo-species comprises at least        about 30% of the composition, and wherein the composition has an        average particle size of at least about 75 microns; or    -   wherein the 1,3-dibromo-species is predominate, and wherein the        1,3-dibromo-species comprises at least about 90% of the        composition; or    -   wherein the 1,3-dibromo-species is predominate, wherein the        1,3-dibromo-species comprises at least about 90% of the        composition, and wherein the composition has an average particle        size of at least about 50 microns; or    -   wherein the 1,3-dibromo-species is predominate, wherein the        1,3-dibromo-species comprises at least about 80% of the        composition, and wherein the composition has an average particle        size of at least about 100 microns; or    -   wherein the 1,3-dibromo-species is predominate, wherein the        1,3-dibromo-species comprises at least about 90% of the        composition, and wherein the composition has an average particle        size of at least about 100 microns.

As used in this document, the term “water-soluble” means that thesubstance being described has at least sufficient solubility in water toform an aqueous solution containing at least a sufficient amount of suchdissolved substance (presumably in ionized form) to enable the operationin which such solution is being used, to be carried out under theparticular conditions in which the solution is being employed. Naturallyit is desirable that the substance have a greater solubility than thisin water under such conditions. However, the term does not mean that thesubstance must dissolve in all proportions in water under suchconditions.

It is to be understood that the reactants and components referred to bychemical name or formula anywhere in this document, whether referred toin the singular or plural, are identified as they exist prior to cominginto contact with another substance referred to by chemical name orchemical type (e.g., another reactant, a solvent, or etc.). It mattersnot what preliminary chemical changes, transformations and/or reactions,if any, take place in the resulting mixture or solution or reactionmedium as such changes, transformations and/or reactions are the naturalresult of bringing the specified reactants and/or components togetherunder the conditions called for pursuant to this disclosure. Thus thereactants and components are identified as ingredients to be broughttogether in connection with performing a desired chemical operation orreaction or in forming a mixture to be used in conducting a desiredoperation or reaction. Also, even though an embodiment may refer tosubstances, components and/or ingredients in the present tense (“iscomprised of”, “comprises”, “is”, etc.), the reference is to thesubstance, component or ingredient as it existed at the time just beforeit was first contacted, blended or mixed with one or more othersubstances, components and/or ingredients in accordance with the presentdisclosure.

Also, even though the claims may refer to substances in the presenttense (e.g., “comprises”, “is”, etc.), the reference is to the substanceas it exists at the time just before it is first contacted, blended ormixed with one or more other substances in accordance with the presentdisclosure.

Except as may be expressly otherwise indicated, the article “a” or “an”if and as used herein is not intended to limit, and should not beconstrued as limiting, the description or a claim to a single element towhich the article refers. Rather, the article “a” or “an” if and as usedherein is intended to cover one or more such elements, unless the textexpressly indicates otherwise.

It will also be understood that the terms “substantial” and“substantially” denote that chemical processes ordinarily do not involveabsolutes. Thus instead of describing a variable as an absolute, it isfar more realistic to describe the variable as being in the substantialvicinity of the expressed variable. For example when describing astoichiometric quantity it is far more realistic to refer to thequantity as being substantially a stoichiometric quantity since oneskilled in the art fully realizes that slight deviations from theabsolute stoichiometry would produce no appreciable difference inresults. Thus in any and all respects, this document should be read withthe application of common sense.

Each and every patent or other publication or published documentreferred to in any portion of this specification is incorporated in totointo this disclosure by reference, as if fully set forth herein.

This invention is susceptible to considerable variation within thespirit and scope of the appended claims.

1. A process for the N-halogenation of at least one 5-hydrocarbylhydantoin and/or at least one 5,5-dihydrocarbyl hydantoin, which processcomprises concurrently feeding into a reaction zone (i) water, inorganicbase, and at least one 5-hydrocarbyl hydantoin and/or at least one5,5-dihydrocarbyl hydantoin, these being fed separately and/or in anycombination(s), (ii) a separate feed of a brominating agent, and (iii) aseparate feed of a chlorinating agent, in proportions such that duringall or substantially all of the time the concurrent feeding is occurringhalogenation of both nitrogen atoms of said 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin occurs and resultant halogenatedproduct precipitates in the liquid phase of an aqueous reaction mixture,and in which the pH of said liquid phase is continuously orsubstantially continuously maintained in the range of about 2.0 to about8.0 during all or substantially all of the time the concurrent feedingis occurring.
 2. A process of claim 1 wherein said pH is in the range ofabout 2.0 to about 5.5.
 3. A process of claim 1 wherein said pH is inthe range of about 5.5 to about 8.0.
 4. A process of claim 2 whereinsaid aqueous reaction mixture is at a temperature in the range of about30 to about 70° C.
 5. A process of claim 2 wherein (ii) is bromine andis fed subsurface to the liquid phase of said reaction mixture andwherein (iii) is chlorine and is fed subsurface to the liquid phase ofsaid reaction mixture.
 6. A process of claim 2 wherein said5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin is a 5-alkylhydantoin or a 5,5-dialkyl hydantoin, and wherein each alkyl groupcontains up to about 6 carbon atoms.
 7. A process of claim 2 wherein theproportions of water, inorganic base, and 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin being fed are such that: A) where theinorganic base has a monovalent cation, there are from about 1.0 toabout 1.5 moles of 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbylhydantoin and from about 2.0 to about 3.0 moles of the base, per literof water; and B) where the base has a divalent cation, there are about1.0 to about 1.5 moles of 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin and from about 1.0 to about 1.5 moles of thebase, per liter of water.
 8. A process of claim 2 wherein (ii) isbromine; wherein said aqueous reaction mixture is at a temperature inthe range of about 30 to about 70° C.; and wherein if said temperatureis above the boiling point of the bromine, the bromine is fed subsurfaceto the liquid phase of said reaction mixture.
 9. A process of claim 8wherein said 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoinis a 5,5-dialkyl hydantoin, and wherein each alkyl group contains,independently, up to 3 carbon atoms.
 10. A process of claim 8 whereinsaid base is sodium hydroxide, and wherein said aqueous reaction mixtureis at a temperature in the range of about 40 to about 60° C.
 11. Aprocess of claim 10 wherein said 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin is 5,5-dimethylhydantoin.
 12. A process ofclaim 2 wherein the water, inorganic base, and 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin of (i) are introduced as a feedsolution formed from all three of them by mixing 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin with an aqueous solution of inorganicbase.
 13. A process of claim 12 wherein the inorganic base used informing said feed solution is a water-soluble basic salt or oxide of analkali metal or an alkaline earth metal.
 14. A process of claim 12wherein the inorganic base used in forming said feed solution consistsessentially of sodium oxide, sodium hydroxide, sodium carbonate, sodiumbicarbonate, potassium oxide, potassium hydroxide, potassium carbonate,potassium bicarbonate, calcium oxide, calcium hydroxide, or a mixture ofany two or more of them; and wherein the amount of such base is thestoichiometric quantity, or is substantially the stoichiometricquantity, theoretically required to fully deprotonate the 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin used in forming said feedsolution.
 15. A process of claim 12 wherein the process is conducted ina batch mode by initiating the concurrent feeds of (i) and (ii) to thereactor containing (a) a solids-containing heel of a reaction mixturefrom a prior reaction in which the halogenated product to be formed hadbeen formed, or (b) a solids-free mother liquor of a reaction mixturefrom a prior reaction in which the halogenated product to be formed hadbeen formed, and discontinuing the concurrent feeds of (i) and (ii) whenthe reactor has been filled to the desired level; wherein said5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin is a 5-alkylhydantoin or a 5,5-dialkyl hydantoin, and wherein each alkyl groupcontains up to about 6 carbon atoms.
 16. A process of claim 2 whereinthe process is conducted in a batch mode by initiating the concurrentfeeds of (i) and (ii) to a reactor containing (a) a solids-containingheel of a reaction mixture from a prior reaction in which thehalogenated product to be formed had been formed, or (b) a solids-freemother liquor of a reaction mixture from a prior reaction in which thehalogenated product to be formed had been formed, and discontinuing theconcurrent feeds of (i) and (ii) when the reactor has been filled to thedesired level.
 17. A process of claim 2 wherein the separate feeds ofbrominating agent and of chlorinating agent are proportioned such that amole ratio of brominating agent to chlorinating agent is within therange of about 1:1 to about 1:2.5.
 18. A process of claim 2 wherein theseparate feeds of brominating agent and of chlorinating agent areproportioned such that a mole ratio of brominating agent to chlorinatingagent is within the range of about 1:2.5 to about 1:4.
 19. A process ofclaim 3 wherein said aqueous reaction mixture is at a temperature in therange of about 30 to about 70° C.
 20. A process of claim 3 wherein (ii)is bromine and is fed subsurface to the liquid phase of said reactionmixture and wherein (iii) is chlorine and is fed subsurface to theliquid phase of said reaction mixture.
 21. A process of claim 3 whereinsaid 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin is a5-alkyl hydantoin or a 5,5-dialkyl hydantoin, and wherein each alkylgroup contains up to about 6 carbon atoms.
 22. A process of claim 3wherein the proportions of water, inorganic base, and 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin being fed are such that: A)where the inorganic base has a monovalent cation, there are from about1.0 to about 1.5 moles of 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin and from about 2.0 to about 3.0 moles of thebase, per liter of water; and B) where the base has a divalent cation,there are about 1.0 to about 1.5 moles of 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin and from about 1.0 to about 1.5 moles of thebase, per liter of water.
 23. A process of claim 3 wherein (ii) isbromine; wherein said aqueous reaction mixture is at a temperature inthe range of about 30 to about 70° C.; and wherein if said temperatureis above the boiling point of the bromine, the bromine is fed subsurfaceto the liquid phase of said reaction mixture.
 24. A process of claim 23wherein said 5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoinis a 5,5-dialkyl hydantoin, and wherein each alkyl group contains,independently, up to 3 carbon atoms.
 25. A process of claim 23 whereinsaid base is sodium hydroxide, and wherein the temperature of saidaqueous reaction mixture is in the range of about 40 to about 60° C. 26.A process of claim 25 wherein said 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin is 5,5-dimethylhydantoin.
 27. A process ofclaim 3 wherein the water, inorganic base, and 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin of (i) are introduced as a feedsolution formed from all three of them by mixing 5-hydrocarbyl hydantoinand/or 5,5-dihydrocarbyl hydantoin with an aqueous solution of inorganicbase.
 28. A process of claim 27 wherein the inorganic base used informing said feed solution is a water-soluble basic salt or oxide of analkali metal or an alkaline earth metal.
 29. A process of claim 27wherein the inorganic base used in forming said feed solution consistsessentially of sodium oxide, sodium hydroxide, sodium carbonate, sodiumbicarbonate, potassium oxide, potassium hydroxide, potassium carbonate,potassium bicarbonate, calcium oxide, calcium hydroxide, or a mixture ofany two or more of them; and wherein the amount of such base is thestoichiometric quantity, or is substantially the stoichiometricquantity, theoretically required to fully deprotonate the 5-hydrocarbylhydantoin and/or 5,5-dihydrocarbyl hydantoin used in forming said feedsolution.
 30. A process of claim 27 wherein the process is conducted ina batch mode by initiating the concurrent feeds of (i) and (ii) to thereactor containing (a) a solids-containing heel of a reaction mixturefrom a prior reaction in which the halogenated product to be formed hadbeen formed, or (b) a solids-free mother liquor of a reaction mixturefrom a prior reaction in which the halogenated product to be formed hadbeen formed, and discontinuing the concurrent feeds of (i) and (ii) whenthe reactor has been filled to the desired level; wherein said5-hydrocarbyl hydantoin and/or 5,5-dihydrocarbyl hydantoin is a 5-alkylhydantoin or a 5,5-dialkyl hydantoin, and wherein each alkyl groupcontains up to about 6 carbon atoms.
 31. A process of claim 3 whereinthe process is conducted in a batch mode by initiating the concurrentfeeds of (i) and (ii) to a reactor containing (a) a solids-containingheel of a reaction mixture from a prior reaction in which thehalogenated product to be formed had been formed, or (b) a solids-freemother liquor of a reaction mixture from a prior reaction in which thehalogenated product to be formed had been formed, and discontinuing theconcurrent feeds of (i) and (ii) when the reactor has been filled to thedesired level.
 32. A process of claim 3 wherein the separate feeds ofbrominating agent and of chlorinating agent are proportioned such that amole ratio of brominating agent to chlorinating agent is within therange of about 1:1 to about 1:2.5.
 33. A process of claim 3 wherein theseparate feeds of brominating agent and of chlorinating agent areproportioned such that a mole ratio of brominating agent to chlorinatingagent is within the range of about 1:2.5 to about 1:4.
 34. A process forthe N-halogenation of at least one 5-hydrocarbyl hydantoin and/or atleast one 5,5-dihydrocarbyl hydantoin, which process comprises: A-1)concurrently or substantially concurrently feeding into in a reactionzone maintained at one or more temperatures in the range of about 20 toabout 80° C., separate feeds of (i) an aqueous solution or slurry formedfrom an inorganic base and at least one 5-hydrocarbyl hydantoin and/orat least one 5,5-dihydrocarbyl hydantoin, (ii) a brominating agent, and(iii) a chlorinating agent; or A-2) concurrently or substantiallyconcurrently feeding into a reaction zone maintained at one or moretemperatures in the range of about 20 to about 80° C., at least fourseparate feeds, one of which is a brominating agent, another of which isa chlorinating agent, and at least two other feeds, at least one ofwhich is selected from (a) and (b); and at least one of which isselected from (c) and (d), wherein (a) is an aqueous solution or slurryformed from an inorganic base, (b) is an aqueous solution or slurryformed from an inorganic base and at least one 5-hydrocarbyl hydantoinand/or at least one 5,5-dihydrocarbyl hydantoin, (c) at least one5-hydrocarbyl hydantoin and/or at least one 5,5-dihydrocarbyl hydantoin,and (d) is an aqueous solution or slurry formed from at least one5-hydrocarbyl hydantoin and/or at least one 5,5-dihydrocarbyl hydantoin; wherein the concurrent or substantially concurrent feeds in A-1 or inA-2 are in proportions such that 5-hydrocarbyl hydantoin and/or5,5-dihydrocarbyl hydantoin is halogenated on both nitrogen atoms bybromine and/or chlorine atoms, and product is formed which precipitatesin the aqueous reaction mixture continuously or substantiallycontinuously during all or substantially all of the time the concurrentfeeding is occurring; and B) preadjusting and/or adjusting orcontrolling (1) the ratio between the brominating agent and thechlorinating agent fed and (2) the amount of inorganic base fed suchthat the pH of the mixture in the reaction zone is continuously orsubstantially continuously maintained at a selected pH in the range ofabout 2.0 to about 5.5 during the time said concurrent or substantiallyconcurrent feeding is occurring.
 35. A process as in claim 34 whereinthe concurrent feeding of A-1 is used.
 36. A process as in claim 35wherein the separate feed of (i) is an aqueous solution or slurry formedfrom an inorganic base and a single 5,5-dialkyl hydantoin, and whereineach alkyl group contains, independently, up to 3 carbon atoms.
 37. Aprocess as in claim 35 wherein the separate feed of (i) is an aqueoussolution or slurry formed from an inorganic base and5,5-dimethylhydantoin.
 38. A process as in claim 35 wherein the separatefeed of (ii) is bromine, and the separate feed of (iii) is chlorine. 39.A process as in claim 35 wherein the separate feed of (i) is an aqueoussolution or slurry formed from an inorganic base and a single5,5-dialkyl hydantoin, and wherein each alkyl group contains,independently, up to 3 carbon atoms, wherein the separate feed of (ii)is bromine, and wherein the separate feed of (iii) is chlorine.
 40. Aprocess as in claim 34 wherein the concurrent feeding of A-2 is used.41. A process as in claim 40 wherein the brominating agent used isbromine and wherein the chlorinating agent used is chlorine.
 42. Aprocess as in claim 40 wherein the at least one 5-hydrocarbyl hydantoinand/or at least one 5,5-dihydrocarbyl hydantoin in each of (b), (c), and(d) is a single 5,5-dialkyl hydantoin, and wherein each alkyl groupcontains, independently, up to 3 carbon atoms.
 43. A process as in claim40 wherein the at least one 5-hydrocarbyl hydantoin and/or at least one5,5-dihydrocarbyl hydantoin in each of (b), (c), and (d) is5,5-dimethylhydantoin.
 44. A process as in claim 40 wherein thebrominating agent used is bromine, wherein the chlorinating agent usedis chlorine, wherein the at least one 5-hydrocarbyl hydantoin and/or atleast one 5,5-dihydrocarbyl hydantoin in each of (b), (c), and (d) is asingle 5,5-dialkyl hydantoin, and wherein each alkyl group contains,independently, up to 3 carbon atoms.
 45. A process as in claim 40wherein the brominating agent used is bromine, wherein the chlorinatingagent used is chlorine, and wherein the at least one 5-hydrocarbylhydantoin and/or at least one 5,5-dihydrocarbyl hydantoin in each of(b), (c), and (d) is 5,5-dimethylhydantoin.
 46. A process of claim 34wherein the separate feeds of brominating agent and of chlorinatingagent are proportioned such that a mole ratio of brominating agent tochlorinating agent is within the range of about 1:1 to about 1:2.5. 47.A process of claim 34 wherein the separate feeds of brominating agentand of chlorinating agent are proportioned such that a mole ratio ofbrominating agent to chlorinating agent is within the range of about1:2.5 to about 1:4.